Now we'll assemble the sign. These steps include:
- Powering the LED panel and Feather/FeatherWing
- Connecting the Feather and FeatherWing to the panel
- 3D printing brackets to attach the diffusion plastic
- Attaching a handle
The panel draws about 2A of current at 5V. The UBEC (universal battery elimination circuit) is a buck converter that will take our roughly ~9.6V of power from the 8 x AA NiMH battery pack and step it down to 5V.
Solder a barrel jack connector so the center leg goes to the positive input wire of the UBEC, and the sleeve leg goes to UBEC ground.
Solder the barrel plug so that the UBEC positive output (red) wire goes to center and the ground to sleeve.
You can then protect the entire circuit with a length of heat shrink tubing as shown here.
Use Velcro or double-stick foam tape to secure the battery pack, to the sign handle as shown. Make sure to adhere the back side of the battery pack, leaving the lid free to replace batteries as needed.
Measure and mark for two ~3mm holes on the top of the handle. Then drill these out and secure the handle using the two M3 x 12mm screws.
Solder male header pins under the Feather as shown here. The Feather will stack on top of the RGB Matrix FeatherWing
3D print the Feather protector linked below and then use short M2.5 standoffs and screws to secure the Feather to it.
Solder female headers to the top of the FeatherWing as shown, and the box header to the underside. This will allow us to stack the Feather on top of the FeatherWing and plug the show shebang into the panel.
Screw the red and black power wires to the terminal block's positive and ground connections respectively. This cable will plug into the power connector on the matrix panel.
Connect to Sign
Plug the FeatherWing into the sign's IDC connector -- make sure to orient it as shown in the photo! (The added resistor and Kapton tape are present due to a reset fix for the gen. 1 board).
Then, stack the Feather on top of the FeatherWing.
Connect the battery pack to the UBEC buck converter and then to the power input of the FeatherWing.
Plug the RGB Matrix FeatherWing power output cable into the panel as shown, and then neaten and secure the UBEC and power wiring with a couple of zip ties.
Throw in a freshly recharged set of NiMH batteries -- these should last about 2-3 hours of constant sign use with typical graphics (full white on all LEDs is the worst case scenario and will deplete the batteries in about an hour), so carry an extra set if you need.
The sign will definitely work in this state, but let's go the extra step and add a sheet of LED diffusion acrylic. This offers the LEDs some protection, and makes the sign much easier to see, especially on video and in pictures. 3D print one set of the brackets linked here to hold the sheet in place.
Lay the diffusion plastic sheet on top of the LED panel as shown with the matte side up.
Slide the 3D printed brackets on, then flip the sign over and fasten them in with the M3 x 8mm screws.